A mobile communication network comprises two parts: a Circuit Switched (CS) domain, and a Packet Switched (PS) domain. The CS domain bears traditional CS voice services, and the PS domain provides PS services. In order to provide multimedia services over a packet network, the mobile communication network further comprises an IP Multimedia Subsystem (IMS). An IMS network can provide multimedia services over a packet network, and provide voice services in place of the CS domain.
In order to implement policy and charging control on a mobile packet network, the 3rd Generation Partnership Project (3GPP) introduces Policy and Charging Control (PCC) architecture. In the PCC architecture, a Policy Control and Charging Rules Function (PCRF) can receive a request from an Application Function (AF) such as a Proxy Call Session Control Function (P-CSCF) in IMS network, generate policy and charging rules, such as generate corresponding Quality of Service (QoS) rules, and deliver the QoS rules to the Packet Data Network (PDN) gateway (PGW) in a Policy and Charging Enforcement Function (PCEF) such as 3GPP Evolved Packet System (EPS) network architecture.
In the foregoing architecture, in the policy request delivered by the AF to the PCRF, a user may be identified by a user identifier or IP address of a piece of User Equipment (UE). But, in the existing IMS network architecture, the IMS network is unaware of the user identifier according to which the UE accesses the mobile packet network.
In practice, the IP addresses allocated by the mobile packet network to a user are not unique globally. For example, the private network IP addresses allocated by the mobile packet network to a UE may be overlapped with each other on different data networks of a mobile packet network. In addition, when the AF and the UE are located on different mobile packet networks, if the address of the UE is allocated by the mobile packet network in the visited area of the UE, the IP address of the UE may be overlapped with the IP address allocated by the home mobile packet network, or other visited mobile packet networks.
In the process of developing the embodiments of present disclosure, the inventor finds that an IP address does not identify a user uniquely in the foregoing scenarios. In this case, when the AF delivers a policy request, the PCRF is unable to determine the user according to the IP address in the policy request, and therefore is unable to make policy and charging decisions.